Lipopolysaccharides of Escherichia coli K12 Strains That Express Cloned Genes for the Ogawa and Inaba Antigens of Vibrio cholerae O1: Identification of O‐Antigenic Factors

Abstract

Structural and serological studies were performed with the lipopolysaccharide (LPS) expressed by Escherichia coli K12 strains No. 30 and No. 64, into which cosmid clones derived from Vibrio cholerae O1 NIH 41 (Ogawa) and NIH 35A3 (Inaba) had been introduced, respectively. The two recombinant strains, No. 30 (Ogawa) and No. 64 (Inaba), produced LPS that included, in common, the O‐polysaccharide chain composed of an α(1 → 2)‐linked N‐(3‐deoxy‐L‐glycero‐tetronyl)‐D‐perosamine (4‐amino‐4,6‐dideoxy‐D‐manno‐pyranose) homopolymer attached to the core oligosaccharide of the LPS of E. coli K12. Structural analysis revealed the presence of N‐(3‐deoxy‐L‐glycero‐tetronyl)‐2‐O‐methyl‐D‐perosamine at the non‐reducing terminus of the O‐polysaccharide chain of LPS from No. 30 (Ogawa) but not from No. 64 (Inaba). Serological analysis revealed that No. 30 (Ogawa) and No. 64 (Inaba) LPS were found to share the group antigen factor A of V. cholerae O1. They were distinguished by presence of the Ogawa antigen factor B [co‐existing with relatively small amounts of the Inaba antigen factor (c)] in the former LPS and the Inaba antigen factor C in the latter LPS. It appears, therefore, that No. 30 (Ogawa) and No. 64 (Inaba) have O‐antigenic structures that are fully consistent with the AB(c) structure for the Ogawa and the AC structure for the Inaba O‐forms of V. cholerae O1, respectively. Thus, the present study clearly confirmed our previous finding that the Ogawa antigenic factor B is substantially related to the 2‐O‐methyl group at the non‐reducing terminus of the α(1 → 2)‐linked N‐(3‐deoxy‐L‐glycero‐tetronyl)‐D‐perosamine homopolymer that forms the O‐polysaccharide chain of LPS of V. cholerae O1 (Ogawa).

The Klebsiella pneumoniae O2a Antigen Defines a Second Mechanism for O Antigen ATP-binding Cassette Transporters

“…The Vibrio cholerae O1 antigen is, in a sense, a hybrid of the two O-PS ABC transporter models. The polymer can be capped with a non-reducing terminal methyl group, and the presence or absence of this moiety dictates the serological difference between the Ogawa and Inaba serotypes (56,57). However, in contrast to the E. coli O9a system, export of the V. cholerae polymer is not dependent on methylation (58).…”

ABC Transporters Involved in Export of Cell Surface Glycoconjugates

“…Although only one glycan backbone is found in O1 serotypes, two subgroups (Inaba and Ogawa) are distinguished on the basis of O-PS serology. The glycan is a homopolymer consisting of ␣1,2-linked 4-amino-4,6-dideoxy-D-mannose (perosamine), and the serological differences result from the presence (Ogawa) or absence (Inaba) of terminal 2-O-methyl residues (55). Ogawa serotypes express both the methylated and nonmethylated versions of the O-PS, indicating that the chain termination residue added by RfbT (WbeT) (151) is not an absolute requirement for export via the ABC transporter.…”

The ABCs (Antibody, B Cells, and Carbohydrate Epitopes) of Cholera Immunity: Considerations for an Improved Vaccine

“…V. cholerae O1 O-SP consists of (1→2)-α-linked 4-amino-4,6-dideoxy-D-mannose (perosamine) whose amino group is acylated with 3-deoxy-L-glycero-tetronic acid (100,101). The terminal sugar of the O-SP differentiates the two O1 serotypes, Inaba and Ogawa (100,101). A 2-O-methyl group defines Ogawa LPS, while the Inaba terminal sugar has a hydroxyl group in that position.…”